Organic dye degradation through peroxymonosulfate catalyzed by reusable graphite felt/ferriferrous oxide: Mechanism and identification of intermediates

A graphite felt/magnetite nanocomposite (GFMN) was synthesized and the corresponding characteristics were studied through X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET) specific surface area and energy dispersive spectroscopy (EDS). Catalytic activity of GFMN was investigated on peroxymonosulfate (PMS) activation to decolorize acid yellow 36 (AY36). Complete decolorization was obtained under conditions of PMS = 2 mM, 128 mg/L GFMN, pH = 6 and 25 min time. Heat regeneration of GFMN was an efficient method for six cycles of reuse. GFMN also exhibited high activity for the activation of other chemical oxidants (persulfate, hydrogen peroxide and percarbonate) to degrade AY36. Both radicals (SO4− and HO) were responsible in the degradation of AY36. Intermediates of AY36 degradation were identified and a plausible pathway was proposed. Overall, GFMN was a reusable, efficient and stable nanocomposite for catalytic degradation of organic pollutants.